JEE Main

you should go for CS.you have gr8 academics.

some colleges like AKG,Jss,Galogotias take admission through jee mains marks for few reserved seats and there is no state quota.

Yes, you can do b.tech from ABES college
You can get your preferred branch in the college through direct admission also.

First of all congratulations on your grand success of getting 90% marks in CBSE as sometimes even jee advanced qualifier can't be able to do so. Now Defining about colleges depends upon factors because your marks can't cross the cut off but there is no need to get worried because you have a superb marks in cbse so there are many good colleges which you can adopt for so best of luck.

Studies have to be focused such that you target improving your fundamentals. D o not try to "learn by heart" by cramming up the study material. Try to understand in a manner that you can also solve related questions with as much ease. Learning by writing is another way. Try to solve as many questions as possible Avhishek.

U can go for some government colleges. Or private colleges. Good luck.

Follow up this link-
https://en.m.wikipedia.org/wiki/List_of_institutes_funded_by_the_Central_Government_of_India

U can look for NITs. If ur rank will be good u can get that. Or if u couldn't get NITs then look for private colleges. Good luck.

70 marks is very less for getting admission in nit . but you may go for counselling. you may wait for next year for getting admission in nit or you can go for private colleges this year.

Yes , you can go for the jee main 2017 but you should apply for makeup also.